Just when I thought I was done writing about the brain, there I was in Lima, Peru, standing face to face with an actual brain floating in a glass globe. I was in a small museum called “The Brain Museum.” Although I have visited many other quirky, out-of-the-way sites in Peru in the past month, I truly did not intend to visit this one. I was quite sure my Peru agenda had nothing to do with Alzheimer’s disease, my mom, her brain or brains in general. My husband and I have been in Peru working on a documentary film project that has to do with a clinic named after my great-uncle, who lived here for 25 years. But we’re also doing a few days of filming for a global health fellowship program affiliated with the University of Washington. And that’s how I found myself face to face with a floating brain, the focal point of an assemblage sculpture called “Custodia, Estudio 1,” created by artist Jose Luis Herrera Gianino. A custodia—or “monstrance” in English—is a glass container on a stand that is used in some Catholic churches to display the communion host, or wafer, representing the bread Jesus broke and shared with his disciples at the Last Supper. “This is my body, broken for you,” Jesus said. “Take, eat, in remembrance of me.” In earlier eras, a custodia was sometimes used to display relics: bits of the bone, hair or clothing of saints. Here, floating in front of me, was the most intimate relic imaginable of [...]